Relay armature structure



July 2, 1968 R. HAYDEN 3,391,360

RELAY ARMATURE STRUCTURE Filed June 10, 1966 IN VEIV TOR RODNE Y HA YDE/V n-(PM PW United States Patent 3,391,360 RELAY ARMATURE STRUCTURE Rodney Hayden, Stoney Creek, Ontario, Canada, assignor to United-Carr Incorporated, Boston, Mass, a corporation of Delaware Filed June 10, 1966, Ser. No. 556,751 1 Claim. (Cl. 335124) ABSTRACT OF THE DISCLOSURE This invention is directed at a relay armature having a one-piece flexible member with an arcuate portion and with a free arm portion which has contacts extending therefrom and a base portion having a flange portion extending therefrom toward the free arm portion. The are portion has a cutout portion formed in the arcuate portion.

This invention relates to improvements in armatures for electrical relays.

It is usual practice in the manufacture of electrical relays to provide some means for adjustment of the relay armature after manufacture, in order that the precise setting for the armature can be obtained. In many cases the adjustment means is provided by screw settings or in other cases a bent tab design is utilized. The necessity for adjustment of the relay armature increases the cost of the relay and for this reason attempts have been made to achieve a design for an armature which will permit the control of the armature setting automatically during manufacture, thus to reduce the cost of the manufacture of the armature.

According to the present invention however, a relay armature is provided which incorporates a means whereby the setting of the armature can be automatically controlled during manufacture thus to reduce the overall cost of the manufacture and to render the mass production of such armatures reasonable from a point of view of cost.-

The present invention accomplishes this object by providing a relay armature formed from a continuous strip of spring material having a flange portion which maintains the relay armature in the set position as desired and according to predetermined conditions.

Other objects and features of the invention will be apparent from the following detailed description and accompanying drawing in which like numerals refer to like parts throughout the various views.

In the drawings:

FIGURE 1 is a top plan view of a relay armature according to the present invention;

FIGURE 2 is a side elevation of the relay armature as shown in FIGURE 1;

FIGURE 3 is an end elevation of the armature as shown in FIGURE 1; and,

FIGURE 4 is a perspective view of a relay incorporating an armature according to the present invention.

With reference to FIGURE 1 to FIGURE 3 a relay armature according to the present invention is shown and indicated generally as 10. The armature comprises a continuous length of spring strip low carbon ferrous material of high hardness and having a free arcuate portion as at 11 extending through substantially 180 of are between the free arm portion 12, extending tangentially therefrom and forming a part thereof, and a base portion as at 13 forming a part thereof, the base portion 13 terminating in a flange portion 14 extending upwardly to the arm portion 12. A lug portion 15 of reduced width is provided on the terminal edge of the flange portion 14 and extends through the slot as at 16 and is bent over to hold the arm portion 12 restrained in a predetermined position.

3,391,369 Patented July 2, 1968 The lug 15 is bent over in a gradual curve, the amount of curving and thus the final position of the end 17 being determined by the tooling producing the armature 10, whereby adjustment of the tooling provides the required final position of arm portion 12 and thus the required adjustment of the relay armature. Once the final position and amount of curvature for the lug 15 has been determined for a particular production run, large quantities of the parts can be run, each having the required setting within the tolerences allowed.

The individual fingers 18 on the armature 10 are provided with the holes 19 into which the contacts as shown in phantom at 20 can be pressed. The contacts can be provided on the upper or under surface of the relay fingers 18 and in addition one or more of the fingers can be removed from the armature in order that different relay configurations can be provided, all from the same basic armature.

In FIGURE 4 the relay armature 10 is shown mounted within a relay structure indicated generally as 21 and it will be seen that an opening as at 22 is provided in the arcuate portion 11 of the armature. By extending the cutout 22 across a portion of the arcuate portion 11 the spring rate of the armature can be controlled and in addition the flow of magnetic flux therethrough can also be directed. By suitably directing the flow of magnetic flux through the armature 10 the closing rate of the armature for a particular coil 23 can be altered and controlled. Thus to control the closing rate of the particular relay the cutout 22 can be varied in height and width, the pattern of the cutout determining the magnetic flux flow and the strength of the spring action.

The armature 10 is preferably formed of a strip of low carbon steel especially 1012 deep draw steel rolled to width, thickness and 98 to 100 Rockwell hardness. Such B scale material will retain its spring characteristics within the limits of flexing operation required for an appar ently indefinite period, tests thereon having exceeded a million cycles without evidence of change in metal structure or surface characteristics or springiness. Because the material is low in carbon content it provides a good magnetically responsive material. The material can be worked or formed either on a press or on rollers. Generally a low carbon low alloy steel of substantially optimum cold working may be regarded as a satisfactory material. The introduction of carbon increases the springiness and a reduction in carbon enhances the magnetic properties.

The reliability of the amature in its springiness depends upon a geometry which limits the functioning thereof during spring action to a modest stressing of the material well within the elastic limit and of the order for example of /1oo or less of the elastic limit of the material thereof. The geometry preferred according to the invention is such that the radius R of the curve portion 11 be of the order of about forty times the thickness through substantially Further the cantilever portion or arm 12 forming an integral extension of the curve portion 11 is of a length C substantially equal to C The arm 12 being of the same material as the curve portion 11 should not be so long that its springiness detracts from the rigidity necessary for it to act as a switching arm but only so long as to develop a suflicient and practical gap between the switch contacts 20. In general therefore the proportions described provide a suitable structure of high reliability and workability in such manner that the angle of flexure A for the arm portion 12 between closed and open positions is small.

In use the relay armature according to the present invention can be installed within a relay structure such as shown in FIGURE 4. During manufacture the flange part 15 can be adjusted to maintain the arm 12 in the required position to control the closingcharacteristics of the armature. The relay armature is mounted on a suitable insulate base having connecting means which serves to mount the coil within the armature whereby a predetermined spacing between the free arm portion of the armature and the coil is obtained. Suitable electrical contacts are provided secured to the base, which in this case are provided at the normally opened type of contacts, having the gap between the open contacts predetermined. If desired some of the fingers 18 can be removed from the armature to provide different relay configurations.

In order to simplify the installation of contacts on the arms of the relay a contact 24 shown on the arm 25 will be provided. In this case the contact 24 is of elongated configuration and is spot welded to the arm 25. In this view only the top contact 24 can be seen out it will be understood that a similar contact arm can be provided on the underside of the relay arm 25 in order to contact the lead out contacts 26. It has been found in high production runs that such a type of relay contact is less costly to install than the aforementioned circular type of contact pressed through holes in the relay arms.

With further references to FIGURES 1, 2 and 3 inclusive the effect of bending the lug is illustrated. It should be noted that the width of the main body portions of the relay armature is given as A and the width of the lug 15 is given as B which is of considerably reduced width. By altering the tooling as aforementioned the different heights as represented by C and D in FIGURE 2 can be obtained or the position of portion 12 and thus the relay arms 13 and 25. It should be noted that the amount of adjustment as shown in FIGURE 2 is somewhat exaggerated in order to be seen clearly on the drawing and that in practice very small adjustments would be required to produce the required position of the relay fingers within the limits allowed.

The cutout 22 within the curved portion 11 directs the magnetic flux lines as represented by 27 and 28 which thus alters the flow characteristic of the flux lines and thus alters the closing characteristics of the relay. As

has been previously stated, the cut out 22 also alters the spring rate of the relay whereby the cut out is quite useful for controlling, closing characteristics.

It will be further understood that although specific embodiments of the invention have herein been described and illustrated, the invention also contemplates such variations as may fall within the scope of the appended claim.

What I claim is:

1. An electrical relay armature comprising: a continuous length of spring strip magnetic material of constant predetermined width and thickness and having an arcuate portion extending through substantially of are between a free arm portion extending tangentially there from and forming a part thereof and a base portion also a part thereof and tangential therefrom; a flange portion extending normal from the termination of said base portion toward said free arm' portion; a lug portion of reduced width to the width of the other portions of said armature, forming a part of said flange portion and ex tending from the termination thereof about midway of the width, said lug being bent in a curve over toward said free arm portion and into contact therewith to restrain same from outward springing due to inherent spring tension of said material, said free arm portion thus being positioned relative to said base portion, bending of said lug portion adjusting this relative position; and at least one contact arm extending from said free arm portion and forming a part thereof, and said arcuate portion having a cut out formed therein to alter the stiffness thereof and to direct the path of magnetic flux therethrough.

References Cited UNITED STATES PATENTS 9/1966 Hayden 335-203 3/1967 Lake 335-187 

